1. The Field of the Invention
The present invention relates to electrical computers and data processing systems. Specifically, the present invention relates to a system and method for efficiently tuning to channels of a variety of different broadcast types.
2. The Prior State of the Art
Multimedia data (e.g., audio, video, and other data) is broadcast using a variety of different transmission technologies.
One of the first major broadcast technologies is radio in which audio data is transmitted over terrestrial airwaves using an analog audio signal blended with a carrier wave. The analog audio signal is blended with the carrier wave in preparation for transmission by varying the amplitude of the carrier wave as in Amplitude Modulation (AM), or by varying the frequency of the carrier wave as in Frequency Modulation (FM). The blended carrier wave is then transmitted using an antenna over “terrestrial airwaves” meaning that the transmission occurs over the air without using a conductive medium and without the aid of an earth orbiting satellite. A radio receiver (also commonly referred to as simply a “radio”) includes an antenna for receiving the blended carrier wave, a tuner for extracting the analog audio signal from the carrier wave, and a speaker for converting the analog audio signal into sound.
A radio station may be licensed to transmit using a carrier wave of a specified frequency. For example, in the United States, AM radio stations may be licensed to broadcast at a specific frequency within the range of from 530 kilohertz to 1.7 megahertz. FM radio stations may broadcast at a specific frequency within the range of from 88 megahertz to 108 megahertz.
Early television technology uses similar technology as radio technology. However, video data and audio data are both transmitted over terrestrial airwaves in the form of an analog signal blended with a carrier wave. In the United States, Very High Frequency (VHF) television channels 2 to 6 are typically transmitted using a carrier wave of a specific frequency in the range of from 55 to 88 megahertz. VHF channels 7–13 use a specific frequency in the range of from 174 to 216 megahertz. Ultra High Frequency (UHF) channels 14–83 use a specific frequency in the range of from 470 to 890 megahertz. The television receiver (also commonly called a “television”) receives the television signal using an antenna, extract the video and audio data from the carrier wave using a tuner, converts the video data into video images using a display, and converts the audio data into sound using a speaker.
In radio and early television technology, broadcasting occurs by transmitting signals over terrestrial airwaves as described above. However, more recently, various other broadcast mediums are used such as cable and satellite networks. In cable networks, television and Internet data are transmitted over the cable network and to a television set or computer connected to the cable network. In satellite networks, the television and Internet data are transmitted to the television or computer using an earth orbiting satellite.
Until recently, television broadcasts used analog signals only. Currently, however, digital television broadcasts are available via satellite using the Digital Video Broadcast Satellite (DVB-S) standard. It is anticipated that in the near future, digital television broadcasts will also be available using terrestrial airwaves and cable. The FCC has mandated many aspects of the Advanced Television Standards Committee (ATSC) standard for broadcasting digital television signals over terrestrial airwaves and cable.
As apparent from the above, there are numerous types of audio or video broadcast types that either now exist or will likely exist including AM radio, FM radio, analog terrestrial airwave, digital terrestrial airwave, analog cable, digital cable, analog satellite, digital satellite and so forth. Some devices may be capable of receiving several of these broadcast types. Typically, a special tuner is required for each broadcast type. Thus, in order to tune to a desired channel, the viewer chooses the broadcast type in order to select the tuner. Next, the viewer selects the channel within that broadcast type. Thus, in order to tune to the desired channel, the viewer must have some knowledge about what channels are contained within each broadcast type. Typically, however, a viewer may not have full knowledge about what channels are offered on a certain broadcast type. This might especially be the case in broadcast types that offer numerous channels.
Also, acquisition of a digital television signal is a multi-step operation that can be significantly slow. For instance, once a tune request is received, the tuner first monitors the digital video stream in order to extract tuning information such as the program number or program identifier from the video stream. Once this necessary information is extracted, the tuner can finally tune to the desired channel. The initial step of extracting the necessary tuning information can take significant time. Thus, many consumers find that channel changing across digital channels can be an annoyingly slow process.
Thus, what is desired is a system and method for more efficiently tuning to a desired channel in a device that receives multiple broadcast types. Furthermore, it would be desirable if such a system and method provided a faster tune to digital channels.